My living room is 13x21x8, and opens to a kitchen and hallway. I have an ep500, and for a period of about 2 days I had 2 ep500's (one was occasionally making noises at high spl's so axiom had sent me a replacement.) They sounded really good, but I think I would rather have an ep800. I haven't heard one yet, but I didn't notice a huge difference between 1 ep500 and 2, (just smoother bass across all seating positions)

-David